1. Field of the Invention
The present invention relates to semiconductor device used in Si-LSI, GaAs-LSI and liquid crystal display(LCD).
2. Related Background Art
In packaging a flip chip, all bumps formed on a semiconductor chip are connected to pads of a substrate. To this end, a technique to keep parallelism between the semiconductor chip and the substrate is very important. A prior art technique to keep parallelism between the semiconductor chip and the substrate includes a method which uses an optical probe. In this method, a probe light is directed to the semiconductor chip and the substrate, a relative inclination between the semiconductor chip and the substrate is measured based on a reflected light, and the parallelism therebetween is adjusted based on the measurement.
Since a recent semiconductor chip is highly integrated, there are many fine ruggedness on the surface of the semiconductor chip. Thus, even if the probe light is directed to the semiconductor chip by using the optical probe, the light is scattered by the fine ruggedness on the surface of the semiconductor chip so that it is difficult to measure the relative inclination between the substrate and the semiconductor chip.
Further, there are a number of fine ruggedness on a surface of a packaging substrate which is basically a ceramic substrate such as Al.sub.2 O.sub.3 or AlN, or a porous metal such as CuW. As a result, even if the probe light is directed to the packaging substrate by using the optical probe, the light is scattered by the fine ruggedness on the surface of the packaging substrate so that it is difficult to measure the inclination of the packaging substrate.